Connection box with slidable plugboard



March 15, 1960 E. J. GUTTRIDGE ET AL CONNECTION BOX WITH SLIDABLE PLUGBOARD Filed May 8, 1956 2 Sheets-Sheet l if 9 Q4 2: o

3- q- .9 M wao I I 999 Q 0 Q To? g f In Deniers March 15, 1960 E. J. 'GUTTRIDGE ETAL 2,929,042

CONNECTION BOX WITH SLIDABLE PLUGBOARD Filed May '8, 1956 2 Sheets-Sheet 2 United States Patent 2,929,042 CONNECTION BOX WITH SLIDABLE PLUGBOARD Eric John Guttridge, Barnes, and David William Skinner,

Lewisham, London, England, assignors, by mesne assignments, to International Computers and Tabulators Limited, London, England, a British company Application May 8, 1956, Serial No. 583,499 Ciaims priority, application Great Britain June 3, 1955 1 Claim. (Cl. 339-18) This invention relates to connection boxes such, for example, as are used with computing or other statistical machines.

As is well understood it is, in statistical machines, often required to route an input to the machine to an output position having a significance difierent from that of the source of derivation of input. In mechanically controlled machines this function is effected by a connection box including crossor Y-wiring and in electrically controlled machines it is usually eltected by a plugboard.

With the kind of plugboard usually employed to efiect cross-connections in electrically controlled machines there is usually entailed a certain amount of rewiring and adjustment in order to modify the cross-connections and this, according to the amount of modification required, results in a fairly long stoppage of the machine during the changeover operations since the plugboard is not an interchangeable part of the machine. It is a main object of the present invention to provide an electrical connection box which includes fixed electrical contacts to cover all connections it may be desired to eitect and to use therewith a connection element, hereinafter referred to as a plugboard, which can be set-up for use at any convenient time and inserted into the box to effect therewith all the desired cross-connections by the mere insertion of the plugboard into the box thereby, since a changeover from one set-up to another consists only in the removal of a plugboard from the machine and the replacement thereof by another pre-set-up plugboard, reducing the standstill time of the machine when efiecting a change of cross-connections.

It is also an object of the invention so to arrange the plugboard that the cross-connections thereof can readily be modified or altered before insertion of the plugboard into the connection box.

In order that the invention may be clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a top plan, with parts broken away, of a connection box according to the invention,

Fig. 2 is a side elevation, partly in section on line II--II, Fig. 1,

Fig. 3 is a view taken on the line lIIIII, Fig. 1,

Fig. i is a section of a part of the connection box and illustrates the manner in which a plugboard is inserted into the connection box,

Fig. 5 is a broken view of the obverse side of a plugboard,

Fig. 6 is a broken view of the reverse side of the plugboard,

Fig. 7 is a section on line VII-VII, Fig. 5,

Fig. 8 is an exploded view illustrating the use of semi-tubular rivets with the plugboard,

Fig. 9 is a diagrammatic pictorial view illustrating an alternative form for the leading edge of a plugboard,

Fig. 10 is a section of a part of the connection box and illustrates a manner of connection to both sides of a plugboard, and

Fig. 11 is a section of a part of a connection box and illustrates an alternative form of connection to a plugboard.

tion box comprises a box-like structure open at one end and having its two opposed wider sides 1, 2, secured in fixed spaced relation to provide a chamber 3 into which a fiat plugboard 4 can he slid and located by the edges 5, 6 and 7, Figs. 5 and 6, thereof relative to resilient contacts to be described below and supported by the side 2 of the connection box.

The sides of the connection box are made of electrically insulating material and the chamber 3 is defined not only by the inner surfaces of the wider upper and lower connection box sides 1 and 2, as viewed in Figs. 2, 3 and 4, but by spacer elements 8 clamped therebetween to be engaged respectively by the side edges 5 and Got the plugboard when the latter is pushed into the chamber 3. -A stop member 9, Figs. 1 and 2, is provided to be The resilient contacts each comprise an electrically conductive ball 10 located in an aperture extending through the side 2 of the connection box. The diameter of the ball is such that it cannot fully enter the chamber 3 and is therefore at all times partially located in the aperture formed in the side 2. An electrically conductive spring 11 is housed in the aperture and tends to force the ball into the chamber 3 and also eifects electrical connection between the ball and a contact tag 12 towhich an electrical lead can be soldered or otherwise secured and by which input impulses are applied to the connection box. In the embodiment of the invention illustrated in the drawings, the resilient contacts are arranged in three columns A, B and C, Fig. 1, extending lengthwise of the chamber 3, and a further column D, Fig. 1, which extends transversely of the length of the chamber 3 to be adjacent to the stop 9. It will be understood that the disposition of the resilient contacts within the connection box can be other than that illustrated in the drawings but will in all instances be such as to ensure that there are sutficient resilient contacts to effect the desired co-operation with the difierent forms of alternative plugboards which it is desired to insert into the chamber 3 from time to time.

The plugboard illustrated in Figs. 5 and 6 is one form of plugboard which can be used with the arrangement of resilient contacts shown in Figs. 1 and 3, and the plugboard 4 consists of a fiat piece of electrically insulated material to the opposite sides of which there are applied what are known in the art as printed wiring. On the obverse side, Fig. 5 the printed wiring comprises a pattern of electrically conductive strips 13a, 13b, 130, there being one set of strips 13a, 13b, 13c, for each column of a record card. In Figs. 5 and 6 it is assumed that the plugboard is for use with a record card containing columns and in these figures are illustrated the" elements shown as rivets 16, Figs. 7 and 8, are insertedthrough aligned holes 17 extending through the electrically conductive strips, the plugboard, and the electrically conductive lines. As shown in Fig. 8, the rivets are of the kind known as semi-tubular rivets, the hollow ends of which can be readily opened out after insertion of the rivet through the plugboard thereby to efiect electrical connection between a strip 13a, 13b, as ap- .epeaeta propriate, and the electrically conductive line appropriated thereto.

The use of semi-tubular rivets 16 facilitates the removal of misplaced rivets, or of rivets to change or modify the plugboard connectionsand the, recess. left after riveting serves-for centering a tool for. knocking out the rivet. Further, since a rivet isretained in-position only by an overturned rim, instead ofby a solid head, there is little likelihoodof damage to the plugboard-when arivet is knocked out.

It will be readily understood that by the arrangement:

herein described with reference to Figs. 5 and'6, an electrically conductive strip 13a canbe connected, as .ap-

lines 15am 15k andhence to resilient, contacts D, Fig. 1;

Theelectrically' conductivestrips ,are also provided withenlargedelectrically conductive areas 18 :which'are engagedby the balls 10 when the plugboard isinserted into the connection box, and'towh'ich pass the input impulsesto the plugboard.

It will beunderstood that the ends 16a, 16b,.Fig. 8, of theends of the rivets will extend beyond the faces of;the..plugboard and, to permit the plugboard. to pass freely into the chamber 3, the sides 1 and 2 thereof aregprovided with grooves 19, Figs. 2.and3, which permit. the free-passage, of theends 16a and 16b.

The;plugboard isofrectangular cross-section andif theleading end of the board, that is the end'7 'first inserted into the chamber 3, is left square, that is substantiallyat right-angles to the length of the board, it

would be impossible for the plugboard to be inserted into the chamber 3. To facilitate the insertion of the plugboard into the chamber 3, the leading endof the plugboardris provided with a chamfer or bevel '20, Figs.

2, 4, 5 and 6,. which forms an acute angle; with-the reverse gsideof the plugboard and extendssubstantially to. that side thereof. Thus, from Fig. 4 it will beseen that as the plugboardis inserted into the chamber 3, the. chamfer-Ztl Will engage the. balls 10 so' that they are.

depressed. intotheir apertures as the plugboard is inserted into the chamber 3. The charnfer 20 also ensures thatzthe plugboard is, not inserted into the chamber in.:an,;upsid.e-down condition thereof, that is acondition in .whichthe balls lti cannot contactthe areas 18,. and stripsla .togl4k, Fig. 5, when the plugboard is in positionv in .th e .chamber because, if the plugboard should beinserted; into .the chamber in the upside-down condi: tiongthereof, the chamfer or bevel 20 will bec reversedfrom theposition illustrated in Fig; 4 and the'leading edge 7 of1the plugboard will engage the balls but'will not-effectv depression thereof.

lnfsomeginstances, as shown in Fig; 10,.ballstl10may be:provided1to cofoperate with both sides ofthe plugboardand the plugboard Will, in such-cases, be-p'rovided with ,adouble bevel 29a, as illustrated in Fig.9 to effect depressionof the balls .as the plugboardiis inserted :into:

the connection box., If this double bevel extends along the wholeof; the leading edge of the-plugboard, the. balls willbe depressed by the plugboardiif it .is inserted into the-chamber the right-way-up or upside-down. -T.o ensure :that the plugboard with a double bevel can only be inserted into the chamber 3 when-it; is correctly oriented,. the double'bevel 29a, Fig. 9, extendsalong onlyithat part of the leading edge 7 which is to be passed through areas in the chamber in which resilient contacts are .located, and a part of the leading edge 7, on one or both sides of the double bevel 24M has only a'single bevel portion .20.. The singlebevel portionlt) co-operateswith Q resilient members,similar to balls 19 and springs 11, whichareprovided solely for the purpose of ensuring orientation of the plugboard, and it will be impossible to insert the plugboard into the chamber in the upside-down condition thereof because the single bevel portion 20 will engagewith the resilient-members but will not effect depression thereof. Only when the plugboard is correctly orie'nted'will the single bevel portion 21 depress the. resilient members cooperating therewith, so that the plugboard can only be inserted into the chamber when it is correctly oriented.

As has been described above the inputs to the connection box are applied through the contact tags 12 and the outputs from the box are made through the column D of balls 19 and contact tags 21, Fig. 2, appropriated thereto, the balls 10 of column D'being arranged to make electrical contact, as appropriate, with the conductive strips 14a to 14k.

In the-foregoingdescription the resilient contacts in'the connection box-have beendescribed as balls, but it will be understood that, if desired, the resilient contacts may be other than balls, for example as shown in Fig. 11, thecontactsmay consist of mushroornlike elements 19a provided'only with a semi-circular portion to make engagement with the areas 18 of'theplugboard.

We claim:

A connection box for effecting electrical connections comprising a housing forming a slot opening through one endof said housing, said housing havinga plurality of bores therein in communication with said slot, electrically conductive contact elements in said bores,-terminals closing the outer ends of said bores and projecting from said housing, electricallyconductive springs in'said bores and compressed between said contact elements and said terminals' and'biasing said contact elements to enter said slot with theinner ends thereof abutting the wall of said slot opposite thewall from which the elements project, the inner ends of said elements having camlike surfaces thereon facing the'entrance to the slot, the surfaces of said elements immediately'above the slot wall from which the elements project and facing the entrance to the slot being disposed substantially perpendicular to saidslot, a plugboard slidable into said slot, said plugboard having circuit completing means thereon for completing preselected circuits between certain of said terminals and arranged so'that the circuits are'completed only when the board is inserted with a'given surface facing a given direction,

and means in said slot for accurately positioning said plugboard, said circuit completing means including contacts -on said plugboard connected in a predetermined arrangement for'engaging certain contact elements when the plugboard is inplace for electrically connecting certain terminals, said plugboard having at least a portion of one transverse corner of the leading edge which is aligned with at least some of said contact elements beveled tobe complementaryto said 'camlike surfaces, so that when the plugboard is inserted into the slot in correct position the beveled-edge cooperates with the cam surfaces of the contact elements to cam the contact elements'into the bores'to permit passage of the plugboard, but if inserted V incorrectly the leading edge Will abut the sides of saidcontact elements'and prevent entry of said plugboard.

' References Cited in the tile of this patent UNITED. STATES PATENTS 

